philfly Posted March 20, 2010 Share Posted March 20, 2010 I am writing this after a bit of a shock. My beloved 55”Overlander Extra has just disappeared in a ball of flames. After fitting a brand new receiver, due to some radio interference problems I decided to put my battery on charge. The battery had only done two circuits before I had to land due to the problems. I left the 3000mAh 5c battery in the airframe and set up the charger, and here is where it all went wrong. I had been distracted somewhat after a fall out with the other half and inadvertently set the charger to 6cell rather than 5. The ‘intelligent ‘ Sigma EQ had no issue with this and charging commenced, balance charging was not carried out due to the position of the lead. After about 35mins I heard noises coming from the next room. I looked in the mirror and the image seemed distorted. I jumped up to find my battery ballooned to twice its size! The distortion was the fumes from the venting cell! I ripped out the charging leads and carried the model quickly outside, I ran into the house to get something to quench the pack when it exploded and burst into flames quickly destroying the model the battery, the hacker A40L motor and all the other electronics including the brand new receiver. I am only grateful that I didn’t leave the house or I would have come home to ashes! As for charging in the airframe, that is a double edged sword, yes I lost the model but I couldn’t have removed the battery from the house without the airframe t hold onto. Lessons learned 1, Do not charge in the house 2, Buy a Lipo safe bag 3, Never leave batteries unattended whilst charging 4, Buy a fire extinguisher 5, Pay more attention to what Im doing and don’t get complacent What I don’t understand is why the charger continued charging at the wrong voltage? Perhaps the voltage left in the pack was enough to fool the charger into believing it was charging a flat 6 cell instead of a partially charged 5cell?Edited By philfly on 20/03/2010 18:16:40 Quote Link to comment Share on other sites More sharing options...
Dusty Posted March 20, 2010 Share Posted March 20, 2010 Thats a scary story... Lucky it was not worse! Sorry you lost your model and other bits but thats better than your house or peoples lives! Just goes to show...... Quote Link to comment Share on other sites More sharing options...
AWM Posted March 20, 2010 Share Posted March 20, 2010 I agree... defo scary, as a newbie to leccy flying I have just ordered a Lipo safe bag. Quote Link to comment Share on other sites More sharing options...
ericrw Posted March 20, 2010 Share Posted March 20, 2010 Thank goodness you came through it alright ! But how as the other half taken it ,after your earlier tiff ?? Quote Link to comment Share on other sites More sharing options...
Merlin spit Posted March 20, 2010 Share Posted March 20, 2010 its all to easy to be distracted at times ,i often worry about keeping my lipos in the house ,ive got no where else thoughand i figure modelshops must keep them inside. Quote Link to comment Share on other sites More sharing options...
birdy Posted March 20, 2010 Share Posted March 20, 2010 Lucky you saw it in time... Fortunately for me my "intelligent" charger requires the balance lead to be plugged in to charge lipos, but has an annoying tendency to recognise the lipo wrong - which is actually a good thing because it means that I have to check the number of cells. A temperature senser is also a useful addition to a charger IMO. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted March 20, 2010 Share Posted March 20, 2010 Glad you escaped with no really serious damage or injury - you have summed it all up really, and as for the charger, well most will recognize the cell count input, and also display what it thinks is connected, based on voltage feedback, but its up to you, the end user, to confirm this before starting the charge. Bad luck, but as I say - could have been a lot worse. Quote Link to comment Share on other sites More sharing options...
Wingman Posted March 20, 2010 Share Posted March 20, 2010 I have to say that's the first case of exploding LiPo I've come across from a reputable source - nasty! Quote Link to comment Share on other sites More sharing options...
Tom Foreman Posted March 20, 2010 Share Posted March 20, 2010 Carefully checks his Wasabi charging on the bench Bad luck, glad the house didn't burn down, its easy to get complacent with these things, but a balance charger like a Cell Pro is a good investment as it does not guess the voltage of the battery as it checks for each cell separately via the balance charge leads, but then again nothing is fool proof. Tom Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted March 20, 2010 Share Posted March 20, 2010 I too am sorry you had this issue and lost your plane and electronics Quite a few errors made there really which may have been reduced by reading the details of previous Lipo issues. Not entirely sure about your lessons list though. 1, Do not charge in the house 2, Buy a Lipo safe bag 3, Never leave batteries unattended whilst charging 4, Buy a fire extinguisher 5, Pay more attention to what Im doing and don’t get complacent Personally I would list like this in order of importance 1, Pay more attention to what Im doing and don’t get complacent 2, Check charger settings before pressing the start button 3, Never leave batteries unattended whilst charging 4, Never charge Lipos in a plane or on a combustable surface (pyrex bowl is ideal) The fire extinguisher is a little pointless since as the Lipo breaks down it generates its own oxygen so the extinguisher is unlikely to help. It may reduce model damage but you would have to apply the extinguisher until the lipo had completely burnt out. At least if you are indoors the temperature is likely to be reasonable so you are unlikely to overcharge the Lipo for temperature reasons, and it is far more comfortable to be indoors watching a lipo than sitting somewhere uncomfortable and possibly chilly. I know it is easy to be wise after the event but I hope you take the above in the way intended. Not as critisism but as a note to all that Lipos, if they are handled with due care are not dangerous. After all would you fill your car with petrol while smoking? Very unlikely Quote Link to comment Share on other sites More sharing options...
Dusty Posted March 20, 2010 Share Posted March 20, 2010 I bet it didnt smell to good either? Quote Link to comment Share on other sites More sharing options...
David Davis Posted March 20, 2010 Share Posted March 20, 2010 Saw a quarter scale Piper Cub belonging to one of my club colleagues touch down a few weeks ago just before the LiPos exploded. He managed to get the smoking LiPos out of the model before too much damage was done. If this had occured 30 seconds beforehand, the model would have caught fire in mid-air. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted March 20, 2010 Share Posted March 20, 2010 And the cause was ? Quote Link to comment Share on other sites More sharing options...
philfly Posted March 21, 2010 Author Share Posted March 21, 2010 All critism is gratefully accepted. This post was just to help others learn from my mistakes before something serious happens, models can be replaced. Quote Link to comment Share on other sites More sharing options...
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